Polyethylene Terephthalate Thin Film Incorporating Green Emitting Up-Conversion Phosphor

Er3+-doped CaTiO3 up-conversion phosphor was prepared by chemical solution method. Host thin film to incorporate up-conversion phosphor was a nanostructured organo-silicon compound prepared from methyl tri-methoxysilane and 3-glycidoxy-propyl-trimethoxy-silane. Further, we prepared a phosphor paste by mixing the organo-silicon compound with 3 mol% Er3+-doped CaTiO3. Subsequently, this paste was coated on polyethylene terephthalate, followed by heat-treatment at 120°C. The visible emission was found to be at the region 525 ~ 530 nm, 540 ~ 560 nm, and 650 ~ 660 nm corresponding to the 2H11/2 ® 4I15/2, 4S3/2 ® 4I15/2, and 4F9/2 ® 4I15/2 transitions of Er3+ ions, respectively. The transmission of performance IR detection cards is to be above 90% in the range from 200 to 1600 nm because the weak infrared light should pump the CaTiO3 up-conversion phosphor. The prepared up-conversion phosphor films can potentially be used as low-power IR detectors in optical fiber communication and medical instrument.